Slack adjusting device



Aug. 21, 1945. E. A. JENKINS 2,383,196

SLACK ADJUSTING DEVICE Filed March 20, 1944 2 Sheets-Sheet l 851Ajenlahs I S' W 1945. E. A. JENKINS SLACK ADJUSTING DEVICE 7 Filed March20, 1944 2 Sheets-Sheet 2 Patented Aug. 21, 1945 UNITED STATES PATENTOFFICE SLACK 8 1 :12 DEVICE Application March 20; :Izlgfo. 527,329

' 4 Claims.

This invention relates to new and useful improvements in slack adjustingdevices.

One object of the invention is to provide improved means for taking upthe slack of a movable member and which is primarily adapted for use inadjusting the length of brake equalizing rods and similar longitudinallymovable rods.

A particular object of the invention is to pro-.

vide an improved slack adjusting device adapted to be used in connectionwith a brake rod or other reciprocal actuating member for automaticallycompensating for wear of the brake shoes or other actuated means, thedevice being operated by the reciprocation of the rod and beinginoperative when no wear occurs so as to require only infrequent manualsetting.

An important object of the invention is to provide an improved slackadJusting device which is adapted to automatically take up the slack ina reciprocal member, such as a brake rod, during reciprocation of themember, whereby the necessity of manually adjusting the length of saidmember under normal operating conditions is rendered unnecessary.

Another object of the invention is to provide an improved slackadjusting device, of the character described, having a pair ofadjustably-connected sections normally reciprocal as a unit and adaptedto undergo longitudinal movement relative to each other whenreciprocated as a unit in one direction beyond a predetermined distance,there being means having connection with each section for automaticallyeilecting such relative longitudinal movement.

A further object of the invention is to provide an improved slackadjusting device, of the character described, having a take-uparrangement associated therewith for automatically shortening the lengthof said device when the same is moved in one direction beyond apredetermined distance, the take-up arrangement being actuated uponmovement of said device in such direction so as to shorten its lengthupon reverse movement thereof to its original or normal position.

A construction designed to carry out the invention will be hereinafterdescribed together with other features of the invention- The inventionwill be more readily understood from a reading of the followingspecification and by reference to the accompanying drawings,

wherein an example of the invention is shown, and wherein:

Figure 1 is a schematic view of the braking system of a railroad carhaving a slack adjusting device, constructed in accordance with theinvention, connected in the equalizer rod,

Figure 2 is an isometric view of lusting device,

Figure 3 is an elevation of the device with its sections in anintermediate position,

Figure 4 is a view, similar to Figure 3, showing the relation of thesections when the device is in full take-up position,

Figure 5 is an enlarged, transverse, vertical sectional view of theouter end of one of the sections,

Figure 6 is an enlarged, transverse, vertical, secthe slack ad tionalview of the device,

, Figure '7 is a view, similar to Figure 5, showing the relation of theparts upon longitudinal movement of the device, and

Figure 8 is an enlarged, isometric view 01' the central portion of thedevice in the same relative position as illustrated in Figure '1.

In the drawings, the numeral l0 designates a slack adjusting devicewhich is adapted to be connected in the equalizer rod H of the usualbraking system in use on railroad cars. As shown in Figure 1, the systemincludes an air-actuated piston I! which has its rod l3 pivotallyconnected by a transverse rod II and a longitudinal. rod IE to the usualbrake shoes (not shown) of one truck of the railroad car. One end of theequalizer rod H is fastened to the intermediate portion of thetransverse rod it, while another transverse rod It has similarconnection with the opposite end of said equalizer rod. A longitudinalrod l1 pivotally connects the brake shoes (not shown) of the other truckto one end of the rod it, which rod has its opposite end pivotallysecured to the underside of the railroad car as shown at It. The latteris the only point of positive connection between the rods of the brakingsystem and the railroad car. Upon actuation of the piston I! to applythe brakes, the parts of the system will assume the position shown indotted lines with the device Ill moving to the right as a unit with theequalizer rod II and all of said parts pivoting from the point I8. Aswill be hereinafter explained, the device I0 is adapted to shorten thelength of the equalizer rod ll upon excessive movement thereof due towear of the brake shoes so as to prevent excessive movement or throw ofthe piston l2. a

As is clearly shown in Figure 2, the slack adjusting device includes apair of overlapping, parallel sections or members l9 and 20 which are ofidentical construction. The members preferably have the form of flatrods, rectangular in each other cross-section, being held contiguous toin ion itudinal alinement by a pair of U-shaped moved away from eachother without manual bracke ts or keepers 2 I. One bracket has its.paraloutward swinging of said latches. a l to lel leg or flangessecured by rivets 22 to the in- For moving the members |9 and re ativebetermediate portion of each member with its closed each other, a gear orsprocket 3f is gnterpozed I end projecting from said member forreceiving a tween the contiguous surfaceso sa d 1:11am rs? the othermember, whereby the members are hdd e i m e Portion thereof- 6 8 f:together against lateral displacement without prekeyed 1' th wisesecured to a trzfiistgerstz stha f venting relative longitudinalmovement thereof. 35 and has i s teeth in nstant wi is F e 31 The outeror free end of each member may be pp sed gear racks 36, one of whichormed reduced in thickness as shown at 23 and may be the contiguous sfac of eac em er y suitconnected in any suitable manner to the adjaablyrecessing he edial portion of said sur ace. cent section of theequalizer rod l|. As will be i A substantially coextensive ang s formedhereinafter more fully explained, the members 310118 each Side Of h a c35 for maintaining the gear 34 in engagement therewith. may be in thesame vertical or horizontal plane.

For releasably connecting the members I! and lb e59 flanges arePreferably made integral g 20 to each other so that the same will movetotheir respective members as are the gear rac gather as a unit with theequalizer rod, a plurality As Figures 2, 2 3 2; wheel of parallelserrations or ratchet teeth 24 are is carried by one end of e th formedin the contiguous surface of each member rotating the gear A clhckwise go adjacent its outer end. Each tooth 24 extends 20 gear will the memberthe 18 i 8 transversely across its member and is directed member 20 to gright a: h I: longitudinally. outwardly thereof. A pawl or shown inFigure toward 6 p051 on own latch 25, having a curved outer end portionwith ure 4- In order to move the members in the complementary ratchetteeth 28 formed on its inreverse direction the gear musti be h g nermostsurface for engaging the teeth 24, is piv- 2o opmsite kw se d retifion atr 3 otally secured to the overlapping inner end of ig h s qg t; t 5 :5I each member by means of a yoke 21 which is 3?: w g gg by rotationformed by increasing the width of and bifurcat- 8 ca y man ing the innerend portion of the latch element. zgg ggg g the members and The innerend of the member engages within the so The construction describedhereinbefore perrecess of the yoke 21 and a pivot pin 28 extends mitsmanual adjustment of the device III so as to transversely through saidmember and the legs of said yoke to pivotally connect the latch 25 tothe shorten or lengthen the muanzer rod member A flat spring 29 securedto the outer ever, it is desirable to automatically shorten the surfaceof the member by a suitable screw 30, ih f i i igg f g g hg r s gi gig;overlies the outer surface of the latch 25 for resil- 1; 5: revent gs ofthe piston iently maintaining its teeth 28 in engagement '2 i p fishthis automatic with the teeth 24 of the other member. since h 139 eachmember is connected to the other member in Justment' an annular ratchetgear or w Is the manner described hereinbelore, it is manifest keyed orotherwise secured to i gg that the members will reciprocate together asa of the shaft opposite e whee an unit with the equalizer rod Howeverdue to adapted to have its teeth engaged by the teeth of the resilient,pivotal connection of the latches, llementary ratchet 1 or ig: t h lsaid members may he moved longitudinally relac ear shOwh in Figure e e wee tive to each Omen 43 is journaled upon the shaft beyond the ratchetwheel 39 and is made integral with or In order to permit manual movementof the otherwise carried by an elongate, flat arm or lever membersrelative to each other, a finger lift 3| is n which has a suitable opemnadjacent one end secured to the outer surface of each latch 25 forthereof for receiving the shift A nut 42 is swinging the sameoutwardly'a'nd thereby moving -'0 screw-threaded upon the outer ehd ofthe shaft its teeth 26 out of engagement with the teeth 24. and a coiled0r helical spring 43 is confined mm For holding the latch in its outwardposition, a said shaft between the nut and the arm 4| f r recess 32 isformed in the internal surface of one maintaining the teeth of theratchet wheels in of the legs of the yoke 27 and is adapted to beengagement. The free end of the arm 4| enengaged by a spring-pressed all33 which is gages within a slotted keeper member or eye-bolt mounted inthe contiguous surface of the member which is adjustably connected tangular as shown in Flgure The ball 33 is m bracket 45 by having one endthereof reduced and spaced from and out 01' engagement with the rescrewthreaded as shown t 45 and xt di @958 32 when teeth the latch areengaged through a slot 41 formed in one leg of the bracket. with theteeth of the member. However, outward A pair of nuts 43 are carried bythe screwswinging of the latch moves the recess into alinethreadedportion of the eye-bolt for clamping the ment with the ball, wherebysaid latch will be bracket leg therebetween and adjustably mainheld insuch outward position until manually taining said eye-bolt in a fixedposition. The wu in rdly. Since the members l9 and 20 other leg of thebracket 45 is provided with a slot are of identical construction and areconnected as 48 so as to permit connection of said bracket to in thesame manner, it is manifest that one memthe underside of a railroad car.A coiled or her may not be 'moved relative to the other helical spring50 connects the end of the arm 4| member without also moving the latterand that adjacent the shaft 35 to the elongate leg of an thecorresponding ends of said members are alangular bracket 5|, the shortleg of which bracket ways equally spaced from the center of the deviceis provided with a slot 52 to permit fastening of l0. Although it isnecessary to swing both latches said bracket to the underside of therailroad car. 25 outwardly in order to move the inner ends of As shownin Figure 2 the spring 54 maintains the the members toward each other,attention is diarm 4| at an inclination when the equalizer rod rected tothe fact that the outwardly-directed II is stationary or in itsnon-operating position. teeth 24 and 26 permit said inner ends to beUpon longitudinal movement of the rod to the right as shown in Figure 1,the device will be moved in a similar direction so as to pivot the armabout the shaft 35 in counter-clockwise direction to a positionsubstantially at a right angle. relative to said device. If the arm 4!is mounted vertically relative to the railroad car,

said arm will be in a substantially vertical position upon movement oftheequalizer rod and adjusting device to the right.

As is clearly shown in Figures '7 and 8, the teeth of the ratchet wheels99 and 49 extend in a clockwise direction so that said ratchet wheel 40may rotate counter-clockwise relative to said ratchet wheel 39 uponmovement of the equalizer rod and adjusting device to the right orforwardly. This counter-clockwise rotation of the ratchet wheel 40 iscaused by the pivoting of the arm 4i to which said ratchet wheel isrigidly connected. Upon each forward movement of the equalizer rod, theteeth of the ratchet wheel 40 will ride in a counter-clockwise directionupon the teeth of the ratchet wheel 39 so as to force or spread aidratchet wheels apart (Figs. 7 and 8). When the equalizer rod returns toits original left-hand position, the teeth 01' the ratchet wheel 49 willmove back into engagement with the teeth of the ratchet wheel 99 asshown in Figures 2 and 6. The spreading or forcing apart of the ratchetwheels is permitted by the resilient, rotatable mounting of the arm 4!and said arm is returned to its original or inclined position by thetension of the spring 50. It is pointed out that the slotted keeper oreye-bolt 44 has a width greater than the thickness of the arm, therebypermitting movement of said arm longitudinally of the shaft 35 andspreading of the ratchet wheels.

In the event that the throw of the piston l2 exceeds a predetermineddistance due to wear of the brake shoes or other failure, thelongitudinal movement of the equalizer rod II and device ill will alsobe excessive. This excessive movement will pivot the arm 4| in acounter-clockwise direction'beyond the position shown in Figure 8 andthereby rotate the teeth of the ratchet wheel 40 in the same directionbeyond the teeth of the ratchet wheel 39. In other words, each tooth ofthe first .ratchet wheel will ride up upon and then over the adjacentclockwise tooth of the second or other ratchet wheel. When the brakesare released so as to return the piston i2, the equalizer rod II and thedevice III to their original or nonoperating positions, which is in aleft-hand direction (Figs. 1 and 2), the arm 4| and its ratchet wheel 49will be rotated in a clockwise direction by the tension of the spring 50as has been exsimilar movement to the other ratchet wheel Manifestly,the member IE! will be moved toward 'the left and the member 20 towardthe right by this clockwise rotation of the ratchet wheels due to asimilar rotation of the shaft 95 and gear 34 and the engagement betweensaid gear and the gear racks 36.

As has been explained, movement of the members is permitted by theresilient pivotal mounting of the latches 25, whereby the teeth 26 ofsaid latches will ride or slide over the teeth 24 so as to move intoengagement with. different teeth. So long as the throw of the piston I2is excessive, the device "I will be actuated upon each application andrelease of the brakes in the manner herel0 inoperative.

inbeforedescribed. However, when the equalizer rod has been shortenedsufficiently to maintain the desired throw of the piston I2, the teethof the ratchet wheel 40 will merely ride up but not over the teeth ofthe ratchet wheel 99 upon each operation of the brakes so as to renderthe device Attention is directed to the fact that the device is soconstructed that only one ratchet tooth 24 of each member will be takenup by the teeth 26 of the latches 25 upon each movement of said membersrelative to each other irrespective of the amount of movement of theequalizer rod, because clockwise rotation of the ratchet wheel 40 islimited by the eye-bolt 44 restricting the pivotal movement of the lever4i. Of course, the device is inoperative when it reaches the positionshown in Figure 4 and it is necessary to manually reset or adjust thesame as has been hereinbeiore fully explained.

It is readily apparent that a relatively simple device for automaticallyadjusting or taking up the slack in a braking system has been provided.The length of the equalizer rod is automatically shortened to compensatefor wear of the brake shoes and thereby prevents overthrow of thepiston. The device may be readily connected in any braking system andmay be manually adjusted with little effort in a short period of time.It is noted that the brackets 45 and 5| may be secured to the undersideof a railroad car so as to depend vertically therefrom or may be mountedso as to extend horizontally thereof. Although the slack adjustingdevice has been shown and described in connection with the brakingsystem of a. railroad car, it is obvious that said device may be usedwith any longitudinally reciprocal member which might need to beshortened due to wear of other mechanisms.

The foregoing description of the invention is explanatory thereof andvarious changes in the size, shape and materials, as well as in thedetails of the illustrated construction may be made, within the scope ofthe appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

1. A slack adjusting device including, a pair of longitudinal membersdisposed in overlapping parallel relationship, the members being movablelongitudinally relative to each other and being reciprocallongitudinally as a unit, means adjustably fastening said members in afixed variable relation, a gear rack formed on each member, a gearinterposed between and meshing with the gear racks for driving the sameand moving the members relative to each other, the gear being reciprocalwith said members, coacting ratchet means having connection with andreciprocal with said gear, one ratchet means being rotatable with thegear, means for limiting reciprocation of the other ratchet means so asto rotate the same relative to the first ratchet means upon suchreciprocation, and means for resisting movement of said second ratchetmeans and for rotating the same in the opposite direction to itsoriginal position upon reverse reciprocation of the members, wherebyexcessive reciprocation will rotate the second ratchet means relative tothe first ratchet means so that upon reverse reciprocation both ratchetmeans will be rotated in the opposite direction to turn the gear anddrive the gear racks for moving said members relative to each other.

2. A slack adjusting device as set forth in claim 1 wherein the meansfor adjustably fastening the longitudinal members in a fixed variablerelation include, latch means pivotally mounted upon the end of eachmember, and coacting means formed on each member for receiving the latchmeans of the other member, the pivotal mounting of said latch meanspermittingmovement of the members relative to. each other.

3. A slack adjusting device including, a 'pair of longitudinal membersdisposed in overlapping parallel relationship, the members being movablelongitudinally relative to each other and being reciprocallongitudinally as a unit, means adjustably fastening said members in afixed variable.

same relative to said first ratchet wheel'upon such reciprocation, andmeans for resisting movement oi said second ratchet wheel and forrotating the same in the opposite direction to its original positionupon reverse reciprocation of the members,

whereby excessive reciprocation will rotate the second ratchet wheelrelative to the first ratchet wheel so that upon reverse reciprocationthe ratchet wheels will be rotated in the opposite direction to turn thegear and drive the gear racks for moving said members relative to eachother. 7

4. A slack adjusting device as set forth in claim 3 wherein the meansfor adjustably fastening the longitudinal members in a fixed variablerelation include, latch means pivotally mounted upon the end of eachmember, and coacting means formed on each member for receiving the latchmeans of the other member, the pivotal mounting of said latch meanspermitting movement of the members relative to each other.

ERNEST A. JENKINS.

